Experimental and Numerical Studies of Siphon Breaker in an Experimental Test Facility

Experimental and Numerical studies of Siphon breaker were carried in an Experimental Test facility to establish siphon breaking phenomena during small breaks for pool type nuclear research reactors. In these reactors, pool water may get drained through siphoning effect in case of a break in the reactor system piping and the minimum reactor core submergence in the reactor pool required for cooling/shielding of the core may not be ensured. Therefore, siphon breakers become a necessity to limit the pool water draining and to keep required submergence of reactor core. Size of siphon breaker line depends on the system piping size, elevation difference between reactor pool water level and break location, size of break, system resistance etc. Experimental studies were carried out for small size pipe relevant to research reactors. Numerical simulations of the siphon breaking studies were also done using system code “RELAP5” and the results were compared with the experimental data. The effect of the various break sizes in the pool outlet line on the undershooting height is presented in this paper.